Angiotensin-1-receptor antagonists

ABSTRACT

In one aspect, this disclosure features compounds of formula (I) or a pharmaceutically acceptable salt thereof: 
       AA1-Arg-Val-AA4-AA5-His-Pro-AA8-OH   (I),
 
     in which AA1, AA4, AA5, and AA8 are defined in the specification. The compounds of formula (I) can be used to treat hypertension (e.g., hypertension induced by pregnancy), preeclampsia, or a renal disease induced by pregnancy.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to European Patent ApplicationSerial No. 16185403.9, filed on Aug. 23, 2016, and U.S. ProvisionalApplication Ser. No. 62/344,831, filed on Jun. 2, 2016. The contents ofthe prior applications are hereby incorporated by reference in itsentirety.

TECHNICAL FIELD

This invention relates to certain angiotensin-1-receptor antagonists, aswell as related compositions and methods.

BACKGROUND

The renin-angiotensin system (RAS) or renin-angiotensin-aldosteronesystem (RAAS) is a hormonal system that regulates blood pressure andfluid balance. Blocking the RAS can reduce blood pressure. As such,clinical interventions blocking RAS, including inhibitors ofangiotensin-converting enzyme (ACE) and angiotensin receptor blockers(ARBs), have been developed to treat hypertension.

Typically, the prohormone angiotensinogen is converted to the inactiveprecursor Angiotensin I, which is then converted by ACE to the activepeptide hormone Angiotensin II (Ang II). Ang II can be furthermetabolized to Ang III, Ang IV, and Ang(1-7).

In humans, Ang II effects are mediated through seven-transmembraneG-protein coupled receptors, including angiotensin-1-receptor (AT1R) andangiotensin-2-receptor (AT2R). The blood pressure effects of Ang II areprimarily mediated by AT1R. Activation of the AT1R can lead to variouseffects, including vasoconstriction leading to increased blood pressure.Conversely, blocking the AT1R can reduce blood pressure. Severalangiotensin receptor blockers have been developed to treat hypertension.

One of the first angiotensin receptor blockers (ARBs) developed was thepeptidic AT1R antagonist saralasin (i.e., [Sar1, Val5, Ala8]AngII) inthe 1970's, which was approved by the FDA and sold as SARENIN in the US.Another peptidic antagonist, sarilesin (i.e., [Sar1, Ile8]AngII) enteredclinical trials in Japan.

Clinical utility of both these compounds was limited by several factors,including partial agonist activity, short duration of action, andadministration by continuous intravenous infusion. Subsequently,research and development activities in this area turned to the sartanclass of non-peptidic small molecule ARBs, such as losartan, valsartan,and others, which did not have partial agonist activity and could begiven orally. Several non-peptidic ARBs have been approved fortherapeutic use, and SARENIN was withdrawn from the market.

The sartan class of non-peptidic small molecule ARBs are not recommendedfor use during pregnancy. Fetal exposure to ARBs can lead to neonataland long-term complications. For example, it has been recommended thatmaternal treatment with the sartans be avoided in second and thirdtrimesters of pregnancy. Thus, there is a lack of treatment options forhypertension disorders during pregnancy.

SUMMARY

This disclosure is based on the unexpected discovery that certainpeptidic compounds exhibited angiotensin-1-receptor antagonistactivities with no or reduced agonist activities. These compounds canalso have reduced fetal exposure and can be effective in treatinghypertension disorders (e.g., chronic hypertension or gestationalhypertension) or preeclampsia during pregnancy without causing fetal orneonatal complications.

In one aspect, this disclosure features compounds of formula (I) orpharmaceutically acceptable salts thereof:

AA1-Arg-Val-AA4-AA5-His-Pro-AA8-OH   (I),

in which AA1 is an amino acid residue selected from the group consistingof sarcosine and ((2S,3R,4R,5R)-2,3,4,5,6-pentahydroxyhexyl)glycine; AA4is an amino acid residue selected from the group consisting of tyrosineor meta-tyrosine, each of which is optionally substituted with at leastone substituent selected from the group consisting of halo and hydroxyl;AA5 is an amino acid residue selected from the group consisting ofvaline, leucine, isoleucine, glycine, alanine, phenylalanine, threonine,lysine, and tyrosine, each of which is optionally substituted with atleast one substituent selected from the group consisting of C₁₋₆ alkyl,C₄₋₆ cycloalkyl, NH₂, aryl, and heteroaryl; and AA8 is an amino acidresidue selected from the group consisting of 1-naphthylalanine,(3-benzothienyl)alanine, and phenylalanine substituted with at least onesubstituent selected from the group consisting of C₁₋₆ alkyl, C₁₋₆haloalkyl, C₄₋₆ cycloalkyl, halo, CN, aryl, and heteroaryl, in which theat least one substituent is at the 2-position on the phenyl ring of thephenylalanine. AA8 is a D-amino acid residue, and each of Arg, Val, AA4,AA5, His, and Pro in formula (I) is an L-amino acid residue.

In another aspect, this disclosure features a pharmaceutical compositioncomprising at least one of the compounds of formula (I) or apharmaceutically acceptable salt thereof and a pharmaceuticallyacceptable carrier.

In another aspect, this disclosure features a method of treatinghypertension (e.g., hypertension induced by pregnancy). The methodincludes administering to a patient in need thereof an effective amountof the pharmaceutical composition described herein.

In still another aspect, this disclosure features a method of treatingpreeclampsia or a renal disease induced by pregnancy. The methodincludes administering to a patient in need thereof an effective amountof the pharmaceutical composition described herein.

In a further aspect, there is provided a composition (e.g. apharmaceutical composition) for use in the treatment of hypertension(e.g., hypertension induced by pregnancy), preeclampsia or a renaldisease (e.g. renal disease induced by pregnancy), the compositioncomprising a compound of formula (I) or a pharmaceutically acceptablesalt thereof and a pharmaceutically acceptable carrier.

In a further aspect, there is provided the use of a compound of formula(I) or a pharmaceutically acceptable salt thereof in the manufacture ofa medicament for the treatment of hypertension (e.g., hypertensioninduced by pregnancy), preeclampsia or a renal disease (e.g. renaldisease induced by pregnancy).

Other features, objects, and advantages will be apparent from thedescription, drawings, and the claims.

DETAILED DESCRIPTION

This disclosure generally relates to AT1R antagonists (e.g., AT1Rantagonist peptides) and their use for treating hypertension,preeclampsia, or a renal disease (e.g., in patients during pregnancy).

In some embodiments, the AT1R antagonist peptides described herein arecompounds of formula (I) or a pharmaceutically acceptable salt thereof:

AA1-Arg-Val-AA4-AA5-His-Pro-AA8-OH   (I).

In formula (I), AA1 is an amino acid residue selected from the groupconsisting of sarcosine and((2S,3R,4R,5R)-2,3,4,5,6-pentahydroxyhexyl)glycine; AA4 is an amino acidresidue selected from the group consisting of tyrosine or meta-tyrosine,each of which is optionally substituted with at least one substituentselected from the group consisting of halo and hydroxyl; AA5 is an aminoacid residue selected from the group consisting of valine, leucine,isoleucine, glycine, alanine, phenylalanine, threonine, lysine, andtyrosine, each of which is optionally substituted with at least onesubstituent selected from the group consisting of C₁₋₆ alkyl, C₄₋₆cycloalkyl, NH₂, aryl, and heteroaryl; and AA8 is an amino acid residueselected from the group consisting of alanine substituted with at leastone substituent selected from the group consisting of 1-naphthylalanine,(3-benzothienyl)alanine, and phenylalanine substituted with at least onesubstituent selected from the group consisting of C₁₋₆ alkyl, C₁₋₆haloalkyl, C₄₋₆ cycloalkyl, halo, CN, aryl (e.g., phenyl, 1-naphthyl, or2-naphthyl), and heteroaryl, in which the at least one substituent is atthe 2-position on the phenyl ring of the phenylalanine. AA8 is a D-aminoacid residue and each of Arg, Val, AA4, AA5, His, and Pro in formula (I)is an L-amino acid residue.

The term “alkyl” refers to a saturated, linear or branched hydrocarbonmoiety, such as —CH₃ or —CH(CH₃)₂. The term “haloalkyl” refers to asaturated, linear or branched hydrocarbon moiety substituted by at leastone halo group (e.g., F, Cl, Br, or I), such as —CH₂Cl or —CF₃. The term“cycloalkyl” refers to a saturated, cyclic hydrocarbon moiety, such ascyclobutyl, cyclopentyl, or cyclohexyl. The term “aryl” refers to ahydrocarbon moiety having one or more aromatic rings. Examples of arylmoieties include phenyl (Ph), phenylene, naphthyl, naphthylene, pyrenyl,anthryl, and phenanthryl. The term “heteroaryl” refers to a moietyhaving one or more aromatic rings that contain at least one heteroatom(e.g., N, O, or S). Examples of heteroaryl moieties include furyl,furylene, fluorenyl, pyrrolyl, thienyl, oxazolyl, imidazolyl, thiazolyl,pyridinyl, pyrimidinyl, quinazolinyl, quinolyl, isoquinolyl,benzothienyl, and indolyl.

In some embodiments, AA4 can be tyrosine optionally substituted with atleast one substituent, in which the at least one substituent is at the3-position on the phenyl ring of the tyrosine. For example, AA4 can betyrosine, meta-tyrosine, 3-hydroxytyrosine, or 3-chlorotyrosine.

In some embodiments, AA5 can be an amino acid residue selected from thegroup consisting of valine, leucine, isoleucine, glycine, alanine,phenylalanine, threonine, lysine, and tyrosine, each of which isoptionally substituted with at least one substituent selected from thegroup consisting of CH₃, cyclobutyl, cyclopentyl, cyclohexyl, NH₂,thienyl, and thiazolyl. For example, AA5 can be valine, isoleucine,cyclobutylglycine, cyclopentylglycine, cyclohexylglycine,cyclohexylalanine, leucine, o-methyl threonine, lysine, phenylalanine,tyrosine, 4-aminophenylalanine, 3-thienylalanine, 2-thienylalanine, or4-thiazolylalanine.

In some embodiments, AA8 can be an amino acid residue selected from thegroup consisting of unsubstituted D-1-naphthylalanine, unsubstitutedD-(3-benzothienyl)alanine, and D-phenylalanine substituted with at leastone substituent selected from the group consisting of CH₃, CF₃, Cl, Br,CN, and phenyl. For example, AA8 can be D-1-naphthylalanine,D-(3-benzothienyl)alanine, D-2-chlorophenylalanine,D-2-bromophenylalanine, D-2-methylphenylalanine,D-2-trifluoromethylphenylalanine, D-2-cyanophenylalanine,D-2-phenylphenylalanine, D-2,4-dichlorophenylalanine, orD-2,6-dimethylphenylalanine. Without wishing to be bound by theory, itis believed that the amino acid residues of AA8 described above can helpreduce or eliminate the angiotensin-1-receptor agonist activities in thecompounds of formula (I).

In some embodiments, when AA5 or AA8 is an amino acid substitute with aheteroaryl group, the heteroaryl group can include one, two, or threearomatic rings, each of which can be a five-membered or six-memberedring. In such embodiments, the heteroaryl group can include one, two,three, or more ring heteroatoms, such as N, O, or S. For example, theheteroaryl group can be a group that includes one aromatic ringcontaining one ring heteroatom (e.g., N, O, or S), one aromatic ringcontaining two ring heteroatoms (e.g., N, O, or S), one aromatic ringcontaining three ring heteroatoms (e.g., N, O, or S), two aromatic ringscontaining one ring heteroatom (e.g., N, O, or S), two aromatic ringscontaining two ring heteroatoms (e.g., N, O, or S), or two aromaticrings containing three ring heteroatoms (e.g., N, O, or S).

In some embodiments, AA1 can be sarcosine. In such embodiments, AA4 canbe tyrosine, meta-tyrosine, 3-hydroxytyrosine, or 3-chlorotyrosine; AA5can be valine, isoleucine, lysine, tyrosine, 4-aminophenylalanine,cyclohexylalanine, cyclopentylglycine, cyclohexylglycine, phenylalanine,o-methyl threonine, 3-thienylalanine, 2-thienylalanine, or4-thiazolylalanine; and AA8 can be D-1-naphthylalanine,D-(3-benzothienyl)alanine, D-2-chlorophenylalanine,D-2-bromophenylalanine, D-2-methylphenylalanine,D-2-trifluoromethylphenylalanine, D-2-cyanophenylalanine,D-2-phenylphenylalanine, D-2,4-dichlorophenylalanine, orD-2,6-dimethylphenylalanine.

In some embodiments, AA1 can be((2S,3R,4R,5R)-2,3,4,5,6-pentahydroxyhexyl)glycine. In such embodiments,AA4 can be tyrosine; AA5 can be valine or cyclohexylglycine; and AA8 canbe D-1-naphthylalanine, D-(3-benzothienyl)alanine,D-2-chlorophenylalanine, D-2-methylphenylalanine, orD-2-phenylphenylalanine.

Exemplary compounds of formula (I) (i.e., Compounds 1-46) include thoselisted in Table 1 below. Table 1 also includes reference compounds 1-4.Unless specified otherwise, the amino acid code in Table 1 refers to itsL-isomer except for Sar (which is achiral) and Glac (whose chirality isnot on the alpha carbon atom).

TABLE 1 Cpd # Compound Names in Abbreviation 1Sar-Arg-Val-Tyr-Val-His-Pro-(D-1Nal)-OH 2Sar-Arg-Val-Tyr-Lys-His-Pro-(D-1Nal)-OH 3Sar-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2-CF₃))—OH 4Sar-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2-Cl))—OH 5Sar-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2-CN))—OH 6Sar-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2-Ph))—OH 7Sar-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2,4-diCl))—OH 8Sar-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2,6-diMe))—OH 9Sar-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2-Me))—OH 10Sar-Arg-Val-Tyr-Val-His-Pro-(D-(3-benzothienyl)alanine)-OH 11Sar-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2-Br))—OH 12Sar-Arg-Val-Tyr-Tyr-His-Pro-(D-1Nal)-OH 13Sar-Arg-Val-Tyr-Aph-His-Pro-(D-1Nal)-OH 14Sar-Arg-Val-Tyr-Cha-His-Pro-(D-1Nal)-OH 15Sar-Arg-Val-Tyr-Cpg-His-Pro-(D-1Nal)-OH 16Sar-Arg-Val-Tyr-Phe-His-Pro-(D-1Nal)-OH 17Sar-Arg-Val-Tyr-Thr(Me)-His-Pro-(D-1Nal)-OH 18Sar-Arg-Val-Tyr-Cpg-His-Pro-(D-Phe(2-Cl))—OH 19Sar-Arg-Val-Tyr-Chg-His-Pro-(D-Phe(2-Cl))—OH 20Sar-Arg-Val-Tyr-Aph-His-Pro-(D-Phe(2-Cl))—OH 21Sar-Arg-Val-Tyr-Thr(Me)-His-Pro-(D-Phe(2-Cl))—OH 22Sar-Arg-Val-Tyr-(3-Thi)-His-Pro-(D-Phe(2-Cl))—OH 23Sar-Arg-Val-Tyr-(2-Thi)-His-Pro-(D-Phe(2-Cl))—OH 24Sar-Arg-Val-Tyr-(Ala(4-Thz))-His-Pro-(D-Phe(2-Cl))—OH 25Sar-Arg-Val-Tyr-Ile-His-Pro-(D-Phe(2-Cl))—OH 26Sar-Arg-Val-Tyr-Chg-His-Pro-(D-Phe(2-CF₃))—OH 27Sar-Arg-Val-Tyr-Chg-His-Pro-(D-Phe(2-Me))—OH 28Sar-Arg-Val-Tyr(3-Cl)-Val-His-Pro-(D-Phe(2-Cl))—OH 29Glac-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2-Cl))—OH 30Sar-Arg-Val-(m-Tyr)-Val-His-Pro-(D-Phe(2-Cl))—OH 31Glac-Arg-Val-Tyr-Chg-His-Pro-(D-Phe(2-Cl))—OH 32Sar-Arg-Val-DOPA-Val-His-Pro-(D-Phe(2-Cl))—OH 33Sar-Arg-Val-Aph-Val-His-Pro-(D-Phe(2-Cl))—OH 34Sar-Arg-Val-Tyr-Chg-His-Pro-(D-1Nal)-OH 35Sar-Arg-Val-Tyr-Chg-His-Pro-(D-(3-benzothienyl)alanine)—OH 36Sar-Arg-Val-Tyr-Chg-His-Pro-(D-Phe(2-Ph))—OH 37Glac-Arg-Val-Tyr-Val-His-Pro-(D-1Nal)-OH 38Glac-Arg-Val-Tyr-Val-His-Pro-(D-(3-benzothienyl)alanine)-OH 39Glac-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2-Ph))—OH 40Glac-Arg-Val-Tyr-Chg-His-Pro-(D-1Nal)-OH 41Glac-Arg-Val-Tyr-Chg-His-Pro-(D-(3-benzothienyl)alanine)-OH 42Glac-Arg-Val-Tyr-Chg-His-Pro-(D-Phe(2-Ph))—OH 43Glac-Arg-Val-Tyr-Cpg-His-Pro-(D-Phe(2-Cl))—OH 44Glac-Arg-Val-Tyr-Cpg-His-Pro-(D-Phe(2-Me))—OH 45Glac-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2-Me))—OH 46Glac-Arg-Val-Tyr-Chg-His-Pro-(D-Phe(2-Me))—OH ReferenceSar-Arg-Val-Tyr-Ile-His-Pro-Ile-OH compound 1 ReferenceSar-Arg-Val-Tyr-Ile-His-Pro-D-Phe-OH compound 2 ReferenceAsp-Arg-Val-Tyr-Ile-His-Pro-Phe-OH compound 3 Reference Valsartancompound 4

The full names of the abbreviations of the native or non-native aminoacids used in this disclosure are summarized in Table 2 below:

TABLE 2 Abbreviation Full name Glac((2S,3R,4R,5R)-2,3,4,5,6-pentahydroxyhexyl)glycine Sar Sarcosine ArgArginine Val Valine Ile Isoleucine His Histidine Pro Proline CbgCyclobutylglycine Cpg Cyclopentylglycine Chg Cyclohexylglycine ChaCyclohexylalanine Leu Leucine Thr(Me) O-Methyl threonine Lys Lysine PhePhenylalanine D-Phe(2-CF₃) 2-Trifluoromethylphenylalanine D-Phe(2-Cl)2-Chlorophenylalanine D-Phe(2-CN) 2-Cyanophenylalanine D-Phe(2-Ph)2-Phenylphenylalanine D-Phe(2-Me) 2-Methylphenylalanine D-Phe(2-Br)2-Bromophenylalanine D-Phe(2,4-diCl) 2,4-DichiorophenylalanineD-Phe(2,6-diMe) 2,6-Dimethylphenylalanine Tyr Tyrosine m-Tyrmeta-Tyrosine DOPA 3-Hydroxytyrosine Tyr(3-Cl) 3-Chlorotyrosine D-1NalD-1-Naphthylalanine Aph 4-Aminophenylalanine 3-Thi 3-Thienylalanine2-Thi 2-Thienylalanine Ala(4-Thz) 4-Thiazolylalanine

In some embodiments, the compound of formula (I) may be

-   -   (4) Sar-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2-Cl))—OH    -   (9) Sar-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2-Me))-OH;    -   (29) Glac-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2-Cl))—OH;    -   (31) Glac-Arg-Val-Tyr-Chg-His-Pro-(D-Phe(2-Cl))—OH;    -   (45) Glac-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2-Me))-OH; or    -   (46) Glac-Arg-Val-Tyr-Chg-His-Pro-(D-Phe(2-Me))-OH.

The AT1R antagonist peptides described herein (e.g., the compounds offormula (I)) can be made by methods known in the art or methodsdescribed herein. Examples 1-6 below provide detailed descriptions ofhow compounds 1-46 were actually prepared.

The reactions for preparing the AT1R antagonist peptides describedherein can be carried out in suitable solvents, which can be readilyselected by one of skill in the art of organic synthesis. Suitablesolvents can be substantially non-reactive with the starting materials(reactants), the intermediates, or products at the temperatures at whichthe reactions are carried out, e.g., temperatures which can range fromthe solvent's freezing temperature to the solvent's boiling temperature.A given reaction can be carried out in one solvent or a mixture of morethan one solvent. Depending on the particular reaction step, suitablesolvents for a particular reaction step can be selected by the skilledartisan.

Preparation of the AT1R antagonist peptides described herein can involvethe protection and deprotection of various chemical groups. The need forprotection and deprotection, and the selection of appropriate protectinggroups, can be readily determined by one skilled in the art. Thechemistry of protecting groups can be found, for example, in T. W.Greene and P. G. M. Wuts, Protective Groups in Organic Synthesis, 3^(rd)Ed., Wiley & Sons, Inc., New York (1999), which is incorporated hereinby reference in its entirety.

The AT1R antagonist peptides described herein can also include allisotopes of atoms occurring in the intermediates or final compounds.Isotopes include those atoms having the same atomic number but differentmass numbers. For example, isotopes of hydrogen include tritium anddeuterium.

All compounds and pharmaceutically acceptable salts thereof, can befound together with other substances such as water and solvents (e.g.hydrates and solvates) or can be isolated.

In some embodiments, the AT1R antagonist peptides described herein aresubstantially isolated. By “substantially isolated” is meant that acompound is at least partially or substantially separated from theenvironment in which it was formed or detected. Partial separation caninclude, for example, a composition enriched with an AT1R antagonistpeptide described herein. Substantial separation can includecompositions containing at least about 50%, at least about 60%, at leastabout 70%, at least about 80%, at least about 90%, at least about 95%,at least about 97%, or at least about 99% by weight of an AT1Rantagonist peptide described herein. Methods for isolating compounds andtheir salts are routine in the art.

This disclosure also features pharmaceutical compositions containing atherapeutically effective amount of at least one (e.g., two or more) ofthe AT1R antagonist peptides described herein (e.g., the compounds offormula (I)) or a pharmaceutically acceptable salt thereof as an activeingredient, as well as at least one pharmaceutically acceptable carrier(e.g., adjuvant or diluent). Examples of pharmaceutically acceptablesalts include acid addition salts, e.g., salts formed by reaction withhydrohalogen acids (such as hydrochloric acid or hydrobromic acid),mineral acids (such as sulfuric acid, phosphoric acid and nitric acid),and aliphatic, alicyclic, aromatic or heterocyclic sulfonic orcarboxylic acids (such as formic acid, acetic acid, propionic acid,succinic acid, glycolic acid, lactic acid, malic acid, tartaric acid,citric acid, benzoic acid, ascorbic acid, maleic acid, hydroxymaleicacid, pyruvic acid, p-hydroxybenzoic acid, embonic acid,methanesulphonic acid, ethanesulphonic acid, hydroxyethanesulphonicacid, halobenzenesulphonic acid, trifluoroacetic acid,trifluoromethanesulphonic acid, toluenesulphonic acid, andnaphthalenesulphonic acid).

The carrier in the pharmaceutical composition must be “acceptable” inthe sense that it is compatible with the active ingredient of thecomposition (and preferably, capable of stabilizing the activeingredient) and not deleterious to the subject to be treated. One ormore solubilizing agents can be utilized as pharmaceutical carriers fordelivery of an active AT1R antagonist peptide. Examples of othercarriers include colloidal silicon oxide, magnesium stearate, cellulose,sodium lauryl sulfate, and D&C Yellow #10.

The pharmaceutical composition described herein can optionally includeat least one further additive selected from a disintegrating agent,binder, lubricant, flavoring agent, preservative, colorant and anymixture thereof. Examples of such and other additives can be found in“Handbook of Pharmaceutical Excipients”; Ed. A. H. Kibbe, 3rd Ed.,American Pharmaceutical Association, USA and Pharmaceutical Press UK,2000.

The pharmaceutical composition described herein can be adapted forparenteral, oral, topical, nasal, rectal, buccal, or sublingualadministration or for administration via the respiratory tract, e.g., inthe form of an aerosol or an air-suspended fine powder. The term“parenteral” as used herein refers to subcutaneous, intracutaneous,intravenous, intramuscular, intraarticular, intraarterial,intrasynovial, intrasternal, intrathecal, intralesional,intraperitoneal, intraocular, intra-aural, or intracranial injection, aswell as any suitable infusion technique. In some embodiments, thecomposition can be in the form of tablets, capsules, powders,microparticles, granules, syrups, suspensions, solutions, nasal spray,transdermal patches or suppositories.

In some embodiments, the pharmaceutical composition described herein cancontain an AT1R antagonist peptide described herein that is dissolved inan aqueous solution. For example, the composition can include a sodiumchloride aqueous solution (e.g., containing 0.9 wt % of sodium chloride)to serve as a diluent.

In addition, this disclosure features a method of using an AT1Rantagonist peptide as outlined above for treating hypertension orpreeclampsia, or for the manufacture of a medicament for such atreatment. The method can include administering to a patient (e.g., apatient during pregnancy) in need thereof an effective amount of thepharmaceutical composition described herein. In some embodiments, thehypertension is induced by pregnancy. In some embodiments, thehypertension can be chronic hypertension or gestational hypertension.“An effective amount” refers to the amount of the pharmaceuticalcomposition that is required to confer a therapeutic effect on thetreated subject. Effective doses will vary, as recognized by thoseskilled in the art, depending on the types of diseases treated, route ofadministration, excipient usage, and the possibility of co-usage withother therapeutic treatment.

As used herein, the terms “treatment,” “treat,” and “treating” refer toreversing, alleviating, delaying the onset of, or inhibiting theprogress of, a disease or disorder described herein or one or moresymptoms thereof. In some embodiments, treatment may be administeredafter one or more symptoms have developed. In other embodiments,treatment may be administered in the absence of symptoms. For example,treatment may be administered to a susceptible individual prior to theonset of symptoms (e.g., in light of a history of symptoms and/or inlight of genetic or other susceptibility factors). Treatment may also becontinued after symptoms have resolved, for example to prevent or delaytheir recurrence.

The typical dosage of the AT1R antagonist peptide described herein canvary within a wide range and will depend on various factors such as theindividual needs of each patient and the route of administration.Exemplary daily dosages (e.g., for subcutaneous administration) can beat least about 0.5 mg (e.g., at least about 1 mg, at least about 5 mg,at least about 10 mg, or at least about 15 mg) and/or at most about 200mg (e.g., at most about 150 mg, at most about 100 mg, at most about 75mg, at most about 50 mg, at most about 20 mg, or at most about 15 mg) ofan AT1R antagonist peptide. The skilled person or physician may considerrelevant variations to this dosage range and practical implementationsto accommodate the situation at hand.

In some embodiments, the pharmaceutical composition described herein canbe administered once daily. In some embodiments, the pharmaceuticalcomposition can be administered more frequent than once daily (e.g.,twice daily, three times daily, or four times daily). In someembodiments, the pharmaceutical composition can be administered by acontinuous infusion, such as intravenous (IV) or subcutaneous (SC)infusion. In some embodiments, the pharmaceutical composition can beadministered less frequent than once daily (e.g., once every two days,once every three days, or once every week).

In addition, this disclosure features a composition as outlined above,for use in treating hypertension or preeclampsia.

In some embodiments, the hypertension is induced by pregnancy. In someembodiments, the hypertension can be chronic hypertension or gestationalhypertension.

The contents of all publications cited herein (e.g., patents, patentapplication publications, and articles) are hereby incorporated byreference in their entirety.

The following examples are illustrative and not intended to be limiting.

EXAMPLES General Synthetic Methods 1. Amino Acid Derivatives

Amino acid derivatives were purchased from commercial providers (such asAapptec, Chem Impex International, EMD Millipore, PPL, PepTech andPeptides International), except for Fmoc-D-Phe(2-Phe) and Fmoc-Thr(Me).Fmoc-D-Phe(2-Phe) and Fmoc-Thr(Me) were prepared as follows:

Synthesis of Fmoc-D-Phe(2-Ph)

Fmoc-D-Phe(2-Br)—OH (923 mg, 2 mmol), phenylboronic acid (366 mg, 3mmol), palladium(II) acetate (22 mg, 0.1 mmol), sodium bicarbonate (504mg, 6 mmol) and 50% acetonitrile-water (10 ml) were combined inside amicrowave-compatible glass vial. Argon was bubbled through the mixturefor 1 minute and the vial was immediately crimped. The reaction mixturewas heated at 70° C. with stirring for 30 minutes inside a microwavereactor (Biotage). Elemental palladium formed during the reaction wasfiltered off on celite. The filtrate was placed in a 50 ml centrifugetube, was acidified with HCl, and was diluted with water to capacity.The oily product was separated by centrifugation. The pellet was washedwith water, dissolved in tent-butanol and lyophilized to give the targetproduct as a white powder. Yield: 930 mg (100%).

Synthesis of Fmoc-Thr(Me)

O-Methyl threonine (2.663 g, 20 mmol) was dissolved in a solution ofsodium bicarbonate (5.04 g, 60 mmol) in water (100 ml). Acetonitrile (50ml) was added, followed by a suspension of Fmoc-OSu (6.747 g, 20 mmol)in acetonitrile (50 ml), delivered in several portions. The reactionmixture was stirred for 2 hours and, during which time, becamehomogenous. It was then acidified with 2 M HCl and was diluted with 100ml of water. The resulting precipitate was collected by filtration,washed with water and dried under vacuum to give the target product as awhite powder. Yield: 6.745 g (95%).

2. Peptide Synthesis

Resins were purchased from Peptides International. D-Glucamine waspurchased from ChemImpex or from TCI America. All additional reagents,chemicals and solvents were purchased from Sigma-Aldrich and VWR.

The compounds described herein were synthesized by standard methods insolid phase peptide chemistry utilizing Fmoc methodology. The peptideswere assembled either manually or automatically using a Tribute peptidesynthesizer or Symphony peptide synthesizer (Protein Technologies Inc.,Tucson, Ariz.), or by combination of manual and automatic syntheses.

Preparative HPLC was performed on a Waters Prep LC System a WatersSunfire C18 column, 100 Å, 5 μm, 30×100 mm at a flow rate of 40 mL/minor on a 50×100 mm column at a flow rate of 80 mL/min. Analytical reversephase HPLC was performed on an Agilent Technologies 1200rr Series liquidchromatograph using an Agilent Zorbax C18 column, 1.8 μm, 2.6×50 mm at aflow rate of 0.6 mL/min or Agilent Zorbax C18 column, 1.8 μm, 4.6×50 mmat a flow rate of 2 mL/min. Final compound analyses were performed on anAgilent Technologies 1200 Series chromatograph by reverse phase HPLC ona Phenomenex Gemini 110 Å C18 column, 3 μm, 2×150 mm at a flow rate of0.3 mL/min. Mass spectra were recorded on a MAT Finnigan LCQelectrospray mass spectrometer or on LTQ XL electrospray massspectrometer (Thermo Scientific). Unless stated otherwise, all reactionswere performed at room temperature. The following standard referenceliterature provides further guidance on general experimental set up, aswell as on the availability of required starting material and reagents:Kates, S. A., Albericio, F., Eds., Solid Phase Synthesis: A PracticalGuide, Marcel Dekker, New York, Basel, 2000; Greene, T. W., Wuts, P. G.M., Protective Groups in Organic Synthesis, John Wiley Sons Inc., 2^(nd)Edition, 1991; Stewart, J. M., Young, J. D., Solid Phase Synthesis,Pierce Chemical Company, 1984; Bisello, et al., J. Biol. Chem. 1998,273, 22498-22505; Merrifield, J. Am. Chem. Soc. 1963, 85, 2149-2154; andChang and White P. D., ‘Fmoc Solid Phase Peptide Synthesis: a PracticalApproach’, Oxford University Press, Oxford, 2000.

The following protecting groups were utilized to protect the given aminoacid side chain functional groups: Pbf(2,2,4,6,7-pentamethyldihydrobenzofuran-5-sulfonyl) for Arg; tBu(t-butyl) for Tyr; Boc (t-butoxycarbonyl) for Lys; and Trt (trityl) forHis.

Each synthesis started with manual attachment of the first amino acid to2-chlorotrityl resin. Generally, Fmoc-amino acid was dissolved indichloromethane (DCM) at the concentration of 0.1-0.2 M, followed byaddition of N,N-diisopropylethylamine (DIPEA) (5 eq). The resultingsolution was added to dry 2-chlorotrityl resin (2 eq). The mixture wasreacted for 4 hours, followed by addition of methanol (10% v/v). Afteranother 30 minutes, the reagents were drained and the resin was washedwith DMF.

Couplings of Fmoc-protected amino acids on the Tribute synthesizer weremediated with HBTU/NMM in DMF. Single cycles of 60 minutes with a3-5-fold excess of activated Fmoc-protected amino acids were used duringthe synthesis. Arginine was coupled over 3 hours. Removal of the Fmocprotecting group was monitored by UV. Multiple (up to 10 times, asneeded) two-minute washes of the peptide resin with 20% piperidine inDMF were performed.

Couplings of Fmoc-protected amino acids on the Symphony synthesizer weremediated with HBTU/DIPEA in NMP. Single cycles of 60 minutes with a3-5-fold excess of activated Fmoc-protected amino acids were used duringthe synthesis. Arginine was coupled over 3 hours. Removal of the Fmocprotecting group was accomplished with two washes of the peptide resinwith 20% piperidine in DMF (5 minutes wash followed by 20 minutes wash).

DIC/HOBt or DIC/Oxyma Pure mediated couplings in DMF were employed forall amino acids in manual mode. Single cycles of at least 2 hours withup to 3-fold excess of activated Fmoc-protected amino acids were usedduring the synthesis. The completeness of couplings was assessed withninhydrin (Kaiser) test. Removal of the Fmoc protecting group wasachieved with two washes of the peptide resin with 20% piperidine in DMF(5 minutes wash followed by 20 minutes wash).

The N-terminal Glac residue was introduced manually in two steps. In thefirst step, bromoacetic acid or chloroacetic acid was coupled on theresin using diisopropylcarbodiimide (DIC) as a coupling reagent. In thesecond step, the resin was reacted with D-glucamine (4 equivalents) inNMP to displace the halogen. The N-bromoacetyl peptide resins werereacted with D-glucamine at room temperature and the N-chloroacetylpeptide resins were reacted at 50° C. D-Glucamine has limited solubilityin NMP. The reactions can be executed with D-glucamine suspended in NMP.Optionally, D-glucamine was first reacted withN,O-bis(trimethylsilyl)acetamide (BSA, 3-6 equivalents) in NMP for up to1 hour to give a solution of silylated D-glucamine. Then the solutionwas added to the N-haloacetyl peptide resin. The reactions withD-glucamine were run for approximately 16 hours.

Upon completion of the peptide synthesis, the peptide resins were washedwith DCM. The resins were treated with 95 TFA/water and TIS (up to 5%v/v) for 2 hours to remove the side-chain protecting groups withconcomitant cleavage of the peptide from the resin. Most of the cleavagecocktail was evaporated, the crude peptides were precipitated withdiethyl ether and separated by centrifugation or filtration.

The crude peptides were dissolved in up to 10 mL of water-acetonitrilemixtures and loaded onto a preparative HPLC column.

Each crude peptide was purified with a trifluoroacetic acid (TFA)buffer, which contained 0.01% TFA in water as Component A and 0.01% TFAin 95% acetonitrile as Component B. The peptides were eluted with agradient of component B. The fractions with a purity exceeding 95%,determined by reverse-phase analytical HPLC, were pooled lyophilized.The compounds prepared were typically found to be at least 95% pure.

Syntheses of specifically illustrated compounds are provided below.

Example 1: Synthesis of Compound 1

The starting 2-chlorotrityl polystyrene resin (Peptides International,catalog number RCT-1083-PI, 1.39 mmol/g), 1.87 g, 2.6 mmol) was reactedwith a solution of Fmoc-D-1-Nal (1.3 mmol) and N,N-diisopropylethylamine(DIPEA, 6.5 mmol) in DCM (25 ml) for 2.5 hours. After MeOH (2.5 ml) wasadded, the mixture was rotated for another 30 minutes. The reagents weredrained and the resin was washed with DMF. The resin was split betweentwo 40 ml reaction vessels (0.65 mmol per vessel).

Solid phase peptide synthesis was performed using Tribute peptidesynthesizer. Couplings of Fmoc-protected amino acids on the Tributesynthesizer were mediated with HBTU/NMM in DMF. Single cycles of 60minutes with 2.5 mmol of activated Fmoc-protected amino acids per vessel(3.8-fold excess) were used during the synthesis. Arginine was coupledover 3 hours. Removal of the Fmoc protecting group was monitored by UV.Multiple (up to 10 times, as needed) two-minute washes of the peptideresin with 20% piperidine in DMF were performed. The following aminoacids were sequentially coupled: Fmoc-Pro-OH, Fmoc-His(Trt)-OH,Fmoc-Val-OH, Fmoc-Tyr(tBu)-OH, Fmoc-Val-OH, Fmoc-Arg(Pbf)-OH,Boc-Sar-OH. At the conclusion of the automated synthesis the resins fromthe two reaction vessels were combined.

The crude peptide was cleaved from the resin with 30 mL of 95% TFA/H₂Oand 1 mL TIS for 2 hours. After the solvent was evaporated, the crudepeptide was precipitated with diethyl ether, isolated by centrifugation,and was dried in-vacuo. Yield of the crude peptide: 1.513 g.

The crude peptide was dissolved in 20 mL of 50% acetonitrile. Thepeptide was purified by preparative HPLC on the 50×100 mM column in tworuns, loading 10 ml of the crude peptide solution per run. The fractionsof lesser purity were combined and were re-loaded on the HPLC column.The pure fractions from the three runs were pooled and lyophilized togive the target Compound 1 as a white powder. Yield: 521.1 mg (29% basedon 74.3% peptide content).

The observed and calculated MS data (i.e., M+H) are provided in Table 3below.

Example 2: Synthesis of Compound 4

The peptide was assembled manually starting from 13.158 g (20 mmol) of2-chorotrityl polystyrene resin (Peptides International, catalog numberRCT-1083-PI, 1.52 mmol/g). A solution of Fmoc-D-Phe(2-Cl) (4.219 g, 10mmol) and DIPEA (8.8 ml, 50 mmmol) in DCM (75 ml) was added to the dryresin. The reaction was run for 6 hours. After methanol (8 ml) wasadded, the mixture was agitated for 30 minutes, the reagents weredrained, and the resin was washed with DMF.

From this point on DIC/Oxyma Pure mediated couplings in NMP wereemployed. Single cycles of at least 2 hours and up to 24 hours with upto 2-fold excess of activated Fmoc-protected amino acids were usedduring the synthesis. The completeness of couplings was assessed withninhydrin test. Removal of the Fmoc protecting group was achieved withtwo washes of the peptide resin with 20% piperidine in DMF (5 minuteswash followed by 20 minutes wash).

First, the (6-8) fragment was assembled by sequential coupling ofFmoc-Pro-OH and Fmoc-His(Trt)-OH, followed by removal of N-terminalFmoc. The resin was washed with DCM and dried in-vacuo. The weight ofthe dried resin was 17.82 g; substitution was 0.56 mmol/g.

The synthesis was continued with 14.29 g (8 mmol) of the (6-8) resin.The following amino acid derivatives were coupled sequentially:Fmoc-Val-OH, Fmoc-Tyr(tBu)-OH, Fmoc-Val-OH, Fmoc-Arg(Pbf)-OH. TheN-terminal Fmoc group was removed to give the (2-8) peptide resin.

At this point the resin was split into two unequal portions: the largerportion (⅝, 5 mmol) was used in the continuing synthesis of Compound 4and the smaller portion (⅜, 3 mmol) was used in the synthesis ofCompound 29 (see below).

Boc-Sar-OH (10 mmol) was coupled on the larger portion of the resin toconclude solid-phase peptide synthesis of Compound 4.

The crude peptide was cleaved from the resin with 80 mL of 95% TFA/H₂Oand 4 ml TIS for 2 hours. After the solvent was evaporated, the crudepeptide was precipitated with diethyl ether, collected by filtration,and dried in-vacuo.

The precipitate (5.01 g) was dissolved in 50 mL of 50% acetonitrile. Thepeptide was purified by preparative HPLC on the 50×100 mM column in fiveruns, loading 10 ml of the crude peptide solution per run. The purefractions were pooled and lyophilized to give the target Compound 4 as awhite powder. Yield: 3039 mg (45% based on 75% peptide content).

The observed and calculated MS data (i.e., M+H) are provided in Table 3below.

Example 3: Synthesis of Compound 9

The peptide was assembled manually starting from 58.8 g (100 mmol) of2-chlorotrityl polystyrene resin (CreoSalus CAT #SC5055, substitution1.7 mmol/g;). A solution of Fmoc-D-Phe(2-Me)-OH (28.1 g, 70 mmol) andDIPEA (49.3 ml, 280 mmmol) in DCM (450 ml) was added to the dry resin.The reaction was run for 2 hours. After methanol (75 ml) was added, themixture was agitated for 10 minutes and the reagents were drained. Theresin was washed with 3×DCM/MeOH/DIEA (17:2:1, v/v/v), 2×DCM, 2×DMF, and2×DCM.

From this point on DIC/Oxyma Pure mediated couplings in NMP wereemployed. Single cycles of at least 2 hours and up to 16 hours with upto 2-fold excess of activated Fmoc-protected amino acids were usedduring the synthesis. The completeness of couplings was assessed withninhydrin test. Removal of the Fmoc protecting group was achieved withtwo washes of the peptide resin with 20% piperidine in DMF (10 minuteswash followed by 30 minutes wash).

First, the (2-8) fragment was assembled by sequential coupling ofFmoc-Pro-OH, Fmoc-His(Trt)-OH, Fmoc-Val-OH, Fmoc-Tyr(tBu)-OH,Fmoc-Val-OH, Fmoc-Arg(Pbf)-OH. The N-terminal Fmoc group on arginine wasremoved.

At this point the resin was split into two unequal portions. The largerportion (⅗, 42 mmol) was used in the continuing synthesis of Compound 9.

Boc-Sar-OH (65 mmol) was coupled on the larger portion of the resin toconclude solid-phase peptide synthesis of Compound 9.

98.6 g of the peptide resin was added to 1 L of cold cocktailTFA/TES/H₂O (94:3:3, v/v/v). The mixture was agitated at roomtemperature for 3 h. The mixture was filtered and resin beads werewashed with 95% TFA (3×70 mL). The filtrate was rotary evaporated toreduce the volume to approximately 150 mL. Diethyl ether (500 mL) wasadded. The precipitate was collected by filtration, washed with ether,and then dried to give the crude product (43.9 g).

HPLC purification of the crude peptide was performed on a C18 column(101.6×250 mm, 16 μm particle size, 100 Å pore size, Kromasil).Component A was 0.1% TFA and component B was 0.1% TFA in 60%acetonitrile. The combined fractions, containing target compound 9 as aTFA salt, were reloaded on the column for salt exchange. The column waswashed with 4 L of 3% acetonitrile in 0.1 M ammonium acetate solution,pH 4.5. Acetate buffer system was used to elute the compound. ComponentA of the acetate buffer system was 1% AcOH and component B was 1% AcOHin 60% acetonitrile. The combined fractions were lyophilized to givetarget Compound 9 as an acetate salt. Yield: 29.532 g (57.9% based on82.5% peptide content).

The observed and calculated MS data (i.e., M+H) are provided in Table 3below.

Example 4: Synthesis of Compound 29

The (2-8) peptide resin described in Example 2 above (3 mmol) wasthoroughly washed with NMP. A solution of chloroacetic acid (15 mmol)and DIC (15 mmol) in NMP (50 mL) was added and the coupling was run for5 hours. The reagents were drained and the resin was washed with NMP.The resin was transferred into a reaction vessel compatible withmicrowave peptide synthesizer Liberty Blue and was washed with NMP onemore time. Solid D-glucamine (12 mmol) was added on top of the wet resinand the vessel was placed inside the reaction chamber of Liberty Blue.NMP (30 ml) was delivered and the reaction mixture was heated at 50° C.by microwave irradiation with concomitant nitrogen agitation for 16hours. The resin was then sequentially washed with DMF, water, methanoland DCM.

The crude peptide was cleaved from the resin with 60 mL of 95% TFA/H₂Oand 3 ml TIS for 2 hours. After the solvent was evaporated, the crudepeptide was precipitated with diethyl ether and isolated bycentrifugation.

The precipitate was dissolved in 40 mL of 50% acetonitrile. The peptidewas purified by preparative HPLC on the 50×100 mM column in four runs,loading 10 ml of the crude peptide solution per run. The pure fractionswere pooled and lyophilized to give the target Compound 29 as a whitepowder. Yield: 2013.5 mg (46% based on 80% peptide content).

The observed and calculated MS data (i.e., M+H) are provided in Table 3below.

Example 5: Synthesis of Compound 43

The starting 2-chlorotrityl polystyrene resin (Peptides International,(catalog number RCT-1083-PI, 1.5 mmol/g, 949 mg, 1.5 mmol) was reactedwith a solution of Fmoc-D-Phe(2-Cl) (316 mg, 0.75 mmol, Chem-Impex) andDIPEA (3.75 mmol, 660 ul) in DCM (10 ml) for 4 hours. After MeOH (1 ml)was added, the mixture was rotated for another 30 minutes. The reagentswere drained and the resin was washed with DMF. One-third of this resin(0.25 mmol) was placed in a Symphony reaction vessel and was used in thesynthesis of Compound 46 using the Symphony peptide synthesizer.

Couplings of Fmoc-protected amino acids on the Symphony synthesizer weremediated with HBTU/DIPEA in NMP. Single cycles of 60 minutes with a4-fold excess of activated Fmoc-protected amino acids were used duringthe synthesis. Arginine was coupled over 3 hours. Removal of the Fmocprotecting group was accomplished with two washes of the peptide resinwith 20% piperidine in DMF (5 minutes wash followed by 20 minutes wash).The following amino acids were sequentially coupled: Fmoc-Pro-OH,Fmoc-His(Trt)-OH, Fmoc-Cyclopentylglycine-OH, Fmoc-Tyr(tBu)-OH,Fmoc-Val-OH, and Fmoc-Arg(Pbf)-OH. The N-terminal Fmoc group was removedand the resin was washed with NMP.

A solution of bromoacetic acid (2.5 mmol) and DIC (2.5 mmol) in NMP (5ml) was added to the resin. The reaction was run for 4 h. The reagentswere drained and the resin was washed with NMP. D-Glucamine (1 mmol) wassuspended in NMP (5 ml). N,O-Bis(trimethylsilyl)acetamide (3 mmol) wasadded to the suspension. The mixture was stirred for 30 minutes, duringwhich time most of D-glucamine dissolved. The near-clear solution ofsilylated D-glucamine was added to the resin. The reaction was runovernight. The regents were drained and the resin was washed with NMP,MeOH and DCM.

The crude peptide was cleaved from the resin with 5 mL of 95% TFA/H₂Oand 0.2 mL TIS for 2 hours. After the solvent was evaporated, the crudepeptide was precipitated with diethyl ether and isolated bycentrifugation.

The precipitate was dissolved in 5 mL of 50% acetonitrile. The peptidewas purified by preparative HPLC on the 30×100 mM column. The purefractions were pooled and lyophilized to give the target compound 43 asa white powder. Yield: 66.6 mg (17% based on 78.7% peptide content).

The observed and calculated MS data (i.e., M+H) are provided in Table 3below.

Example 6: Synthesis of Compound 46

The starting 2-chlorotrityl polystyrene resin (Peptides International,(catalog number RCT-1083-PI, 1.52 mmol/g), 2.632 g, 4 mmol) was reactedwith a solution of Fmoc-D-Phe(2-Me) (2 mmol) and DIPEA (10 mmol) in DCM(20 ml) for 4 hours. After MeOH (2 ml) was added, the mixture wasrotated for another 30 minutes. The reagents were drained and the resinwas washed with DMF. Half of the resin (1 mmol) was split between fourSymphony reaction vessels (0.25 mmol per vessel). Solid phase peptidesynthesis was continued on Symphony peptide synthesizer in parallel,using an identical coupling protocol for each vessel.

Couplings of Fmoc-protected amino acids on the Symphony synthesizer weremediated with HBTU/DIPEA in NMP. Single cycles of 60 minutes with a4-fold excess of activated Fmoc-protected amino acids were used duringthe synthesis. Arginine was coupled over 3 hours. Removal of the Fmocprotecting group was accomplished with two washes of the peptide resinwith 20% piperidine in DMF (5 minutes wash followed by 20 minutes wash).The following amino acids were sequentially coupled: Fmoc-Pro-OH,Fmoc-His(Trt)-OH, Fmoc-Cyclohexylglycine-OH, Fmoc-Tyr(tBu)-OH,Fmoc-Val-OH, and Fmoc-Arg(Pbf)-OH. The N-terminal Fmoc group was removedand the resins were combined within a 40 ml quartz reaction vesselcompatible with the Tribute peptide synthesizer. The (2-8) peptide resinwas thoroughly washed with NMP.

A solution of chloroacetic acid (5 mmol) and DIC (5 mmol) in NMP (15 mL)was added and the coupling was run for 16 hours on the Tributesynthesizer. The reagents were drained and the resin was washed withNMP. Solid D-glucamine (4 mmol) was added on top of the wet resinfollowed by NMP (20 ml). The reaction vessel was placed on the Tributesynthesizer and was heated at 50° C. by IR irradiation with concomitantvortexing for 16 hours. The resin was then sequentially washed with DMF,water, methanol and DCM.

The crude peptide was cleaved from the resin with 20 mL of 95% TFA/H₂Oand 0.5 ml TIS for 2 hours. After the solvent was evaporated, the crudepeptide was precipitated with diethyl ether and isolated bycentrifugation.

The precipitate was dissolved in 20 mL of 50% acetonitrile. The peptidewas purified by preparative HPLC on the 50×100 mM column in two runs,loading 10 ml of the crude peptide solution per run. The pure fractionswere pooled and lyophilized to give the target compound 46 as a whitepowder. Yield: 601.2 mg (38% based on 75.7% peptide content).

The observed and calculated MS data (i.e., M+H) are provided in Table 3below.

Example 7: Synthesis of Compound 31

The starting 2-chlorotrityl polystyrene resin (Peptides International,(catalog number RCT-1083-PI, 1.58 mmol/g), 1.266 g, 2 mmol) was reactedwith a solution of Fmoc-D-Phe(2-Cl) (422 mg, 1 mmol) and DIPEA (880 μl,5 mmol) in DCM (10 ml) for 4 hours. MeOH (1 ml) was added and themixture was rotated for another 30 minutes. The reagents were drainedand the resin was washed with DMF. The resin was split between fourSymphony reaction vessels (0.25 mmol per vessel). Solid phase peptidesynthesis was continued on Symphony peptide synthesizer in parallel,using an identical coupling protocol for each vessel.

Couplings of Fmoc-protected amino acids on the Symphony synthesizer weremediated with HBTU/DIPEA in NMP. Single cycles of 60 minutes with a4-fold excess of activated Fmoc-protected amino acids were used duringthe synthesis. Arginine was coupled over 3 hours. Removal of the Fmocprotecting group was accomplished with two washes of the peptide resinwith 20% piperidine in DMF (5 minutes wash followed by 20 minutes wash).The following amino acids were sequentially coupled: Fmoc-Pro-OH,Fmoc-His(Trt)-OH, Fmoc-Cyclohexylglycine-OH, Fmoc-Tyr(tBu)-OH,Fmoc-Val-OH, and Fmoc-Arg(Pbf)-OH. The N-terminal Fmoc group was removedand the resins were combined within a manual peptide synthesis vessel.The (2-8) peptide resin was thoroughly washed with NMP.

A solution of bromoacetic acid (1.389 g, 10 mmol) and DIC (1.54 ml, 10mmol) in NMP (20 mL) was added and the coupling was run overnight. Thereagents were drained and the resin was washed with NMP.

D-glucamine (725 mg, 4 mmol) was suspended in NMP (40 ml), followed byaddition of N,O-bis(trimethylsilyl)acetamide. The mixture was stirredfor 30 min. to give a near-clear solution of silylated D-glucamine. Thesolution was added to the resin and the reaction was run overnight. Theresin was then sequentially washed with DMF, methanol and DCM.

The crude peptide was cleaved from the resin with 20 mL of 95% TFA/H₂Oand 0.5 ml TIS for 2 hours. After the solvent was evaporated, the crudepeptide was precipitated with diethyl ether and isolated bycentrifugation.

The precipitate was dissolved in 20 mL of 50% acetonitrile. The peptidewas purified by preparative HPLC on the 50×100 mM column in two runs,loading 10 ml of the crude peptide solution per run. The pure fractionswere pooled and lyophilized to give the target Compound 31 as a whitepowder. Yield: 384 mg (32% based on 83.5% peptide content).

The observed and calculated MS data (i.e., M+H) are provided in Table 3below.

Example 8: Synthesis of Compounds 2, 3, 5-8, 10-28, 30, 32-42, 44 and 45

Compounds 2, 3, 5-8, 10-28, 30, 32-42, 44, and 45 were synthesized byusing the methods described in Examples 1-7.

The observed and calculated MS data (i.e., M+H) of Compounds 1-46, aswell as the purity of these compounds, are summarized in Table 3 below.

TABLE 3 Compound Calculated Observed No. M + H M + H % Purity 1 1038.51038.8 96.7 2 1067.6 1067.7 100.0 3 1056.5 1056.6 99.5 4 1022.5 1022.798.2 5 1013.5 1013.7 100.0 6 1064.6 1064.7 97.9 7 1056.5 1056.5 99.5 81016.6 1016.7 98.7 9 1002.5 1002.6 98.4 10 1044.5 1044.4 98.7 11 1066.41066.6 99.0 12 1102.5 1102.6 98.9 13 1101.6 1101.7 97.0 14 1092.6 1092.798.9 15 1064.6 1064.7 99.4 16 1086.5 1086.7 100.0 17 1054.5 1054.7 99.618 1048.5 1048.7 86.5 19 1062.5 1062.7 100.0 20 1085.5 1085.6 98.2 211038.5 1038.7 99.1 22 1076.5 1076.5 96.6 23 1076.5 1076.5 97.5 24 1077.41077.5 94.9 25 1036.5 1036.5 98.5 26 1096.6 1096.7 99.8 27 1042.6 1042.798.7 28 1056.5 1056.6 95.2 29 1172.5 1172.6 100.0 30 1022.5 1022.5 86.531 1212.6 1212.7 99.7 32 1038.5 1038.5 98.3 33 1021.5 1021.5 98.5 341078.6 1078.7 95.6 35 1084.5 1084.6 99.2 36 1104.6 1104.7 97.4 37 1188.61188.7 97.1 38 1194.6 1194.7 99.7 39 1214.6 1214.7 99.3 40 1228.6 1228.796.2 41 1234.6 1234.7 97.7 42 1254.6 1254.7 100.0 43 1198.6 1198.6 99.544 1178.6 1178.8 97.2 45 1152.6 1152.8 99.5 46 1192.6 1192.9 99.1

Example 9: AT1 Receptor Agonist and Antagonist Activity Measured byFLIPR Assay

AT1 receptor (AT1R) agonists increase intracellular flux of calciumions. AT1R antagonists can reduce the agonist effect. Agonist andantagonist activity of Compounds 1-46 described above was assessed in acell-based Fluorescence Imaging Plate Reader (FLIPR) assay. Compoundswere first tested for agonism (Part I) followed by addition of the AT1Ragonist angiotensin II to test for antagonist activity (Part II). Thisassay used a stable hAT1R expressing cell line (ChanTest hAT1R; ChanTestCorp A628). Intracellular flux of calcium in response to agonist wasmeasured through real-time measurement of fluorescence induced throughthe interaction of Ca2+ (released from intracellular stores) andcalcium-sensitive dye. In Part I, cells were exposed to varyingconcentrations of test compounds and immediately measured for agonistactivity (EC50 and Efficacy). In Part II, following a 20-minuteincubation with test compounds, a fixed concentration of agonist(Angiotensin II) was added and the resulting fluorescence again wasmeasured to determine antagonist activity (IC50 and Efficacy).

ChanTest hAT1R stable cells were maintained in Ham's F12 containing 10%(v/v) heat inactivated fetal bovine serum (FBS-HI), 4 mM Glutamax, 1%NEAA, 50 ng/mL plasmocin, 400 μg/mL G418 at 37° C. under 5% CO₂ in ahumidified atmosphere.

For FLIPR assay, ChanTest hAT1R cells were trypsinized with 6 ml ofTrypsin EDTA solution and harvested in phenol-red free DMEM containing10% FBS-HI, 4 mM Glutamax and counted, spun down and resuspended in thesame medium. The cell suspension was added to the wells of 384-wellblack PDL clear bottom plates at 2.5×10⁴ cells/well, 20 μl/well.

FLIPR Assay Preparation of Loading Buffer

-   -   Loading Buffer: 1 vial of Calcium 5 Bulk Assay reagent was        dissolved in 100 ml of 1×HBSS-20 mM Hepes buffer.    -   Probenecid was resuspended at 1 M in 1 M NaOH. Once the        probenecid had gone into solution, an equal volume of H₂O was        added to make a solution of 500 mM followed by a 1:100 dilution        in the Loading Buffer for a working concentration of 5 mM. The        pH was adjusted to 7.4 using 1 M NaOH.

Loading the Cells With Loading Buffer

-   -   Cell plates were removed from the incubator and 25 μl of Loading        Buffer containing probenecid (5 mM) added to each well.    -   Plates were incubated for 1 hour at 37° C. under 5% CO₂ in a        humidified atmosphere.

Acquisition of Calcium Image

-   -   FLIPR Tetra was setup with the following default parameters and        a read mode with an excitation wavelength of 470-495 nm and an        emission wavelength of 515-575 nm as determined by filter        selection:        -   Gain of 50        -   Excitation Intensity of 80% (Default)        -   Exposure Time of 0.4 seconds (Default)    -   The cell plate was transferred to the FLIPR Tetra, along with        the 384 well compound plate. The remaining steps of the assay        were carried forward by FLIPR Tetra. A baseline reading was        taken at 1-second (s) intervals for 10 s followed by the        addition of 5 μl of 10×compounds. The compound-induced        fluorescence signal was then measured for 3 minutes with        readings taken at 1-s intervals.    -   The cell plate was removed from the FLIPR and set aside for an        additional 17 minutes.    -   The cell plate was then transferred back to the FLIPR Tetra,        along with the 384 well Angiotensin II agonist dilution plate. A        baseline reading was taken at 1-second (s) intervals for 10        seconds, followed by the addition of 5.5 μl of 10×Angiotensin II        agonist. The agonist-induced fluorescence signal was then        measured for 3 minutes with readings taken at 1-s intervals.    -   Overall, each well in the FLIPR assay was composed of the        following components in a total volume of 55.5 μl:    -   20 μl 2.5×10⁴ cells    -   25 μl Calcium 5 Loading Buffer    -   5 μl 10×test or reference compound    -   5.5 μl 10×Angiotensin II agonist (10 nM final concentration)

Time-course results from the FLIPR Calcium 5 assay were expressed asrelative fluorescence light units (RFU). The maximum minus minimumvalues (Max−Min) were used to quantify the strength of the signal. MeanRFU were calculated from replicate values and plotted on the y-axisversus compound concentration on a logarithmic scale on the x-axis, anda single-binding site, four parameter concentration response model:(MIN+((MAX−MIN)/(1+((EC50/x){circumflex over ( )}Hill)))), was used toperform non-linear regression analysis, generating concentrationresponse curves. Reported parameters included agonist potency EC50 (theconcentration causing half-maximal agonist response), antagonist potencyIC50 (the concentration causing half-maximal inhibition of the agonistresponse for antagonist compounds) and efficacy (% MPE: percent of themaximal possible effect).

Compounds 1-46 and four reference compounds were tested in the aboveassay. The four references compounds are: (1) sarilesin (i.e., [Sar1,Ile8]AngII: Sar-Arg-Val-Tyr-Ile-His-Pro-Ile-OH, (“Reference Compound1”), (2) [Sar1, D-Phe8]AngII: Sar-Arg-Val-Tyr-Ile-His-Pro-D-Phe-OH(“Reference Compound 2”), Samanen et al. J. Med. Chem 1988, 31, 510-516,(3) Angiotensin II: Asp-Arg-Val-Tyr-Ile-His-Pro-Phe-OH (i.e., anendogenous agonist having no antagonist activity) (“Reference Compound3”), and (4) valsartan (“Reference Compound 4”). The results aresummarized in Table 4 below.

As shown in Table 4, Compounds 1-46 exhibited similar antagonisticactivity as reference antagonists (i.e. Reference Compounds 1, 2 and 4)and had significantly reduced agonist activities compared to referencepeptidic AT1R antagonists (i.e., Reference Compounds 1 and 2), whichsuggests that these compounds can be used to treat disorders (e.g.,hypertension disorders, preeclampsia, or renal diseases) in patientsduring pregnancy without causing an unwanted pressor effect.

TABLE 4 hAT1R Agonist hAT1R Antagonist Efficacy Agonist IC50 AveEfficacy Antag Cpd No. (%) Ave (nM) (%) Ave 1 5 10.6 99 2 1 16.5 100 3 523.6 99 4 6 10.7 99 5 5 59.6 100 6 10 16.6 99 7 12 6.4 99 8 3 8.5 101 94 13.9 99 10 5 9.5 99 11 4 8.7 99 12 5 3.4 100 13 7 3.2 100 14 5 8.0 10015 6 4.6 100 16 6 5.0 99 17 4 6.0 100 18 3 10.1 99 19 8 14.1 99 20 5 5.299 21 2 10.6 99 22 3 5.0 99 23 4 5.2 98 24 4 7.0 99 25 2 11.6 100 26 1232.9 99 27 8 14.5 100 28 5 12.2 99 29 6 19.5 99 30 12 20.5 100 31 6 15.799 32 5 24.1 99 33 3 17.1 100 34 5 15.5 100 35 6 14.3 100 36 13 26.0 10037 7 19.5 99 38 5 18.8 101 39 8 26.7 101 40 5 21.9 101 41 5 19.1 101 4210 28.5 101 43 6 16.6 100 44 7 20.4 101 45 6 18.6 101 46 6 22.2 100 Ref.Cpd. 1 42 14.2 99 Ref. Cpd. 2 25 14.3 99 Ref. Cpd. 3 100 N/A N/A Ref.Cpd. 4 0.7 40.7 100

Example 10: Evaluation in an In Vivo Animal Model of Preeclampsia

Compounds described in this disclosure were evaluated in an in vivoanimal model of preeclampsia, as described by Hering, et al.,Hypertension 2010, 56, 311-318 with modifications. Briefly,timed-pregnant vendor-catheterized (jugular and carotid vessels) ratsarrived on gestational day (GD) 10, for use in experiments from GD13 to20. Maternal body weights (BW) from GD10-12 were used to help predictpregnancy status for treatment designation. On GD12, rats were assignedto treatment groups. On GD13, rats were typically implanted with ALZET®pumps, one containing angiotensin II (or saline for control rats, IVinfusion) and one containing a test compound (or vehicle for controlrats, SC infusion). From GD14 to GD20, daily BW measurements wereperformed. Within GD14 to GD19, mean arterial pressure (MAP)measurements were taken at least on two separate days (GD14 and GD17),but may be as often as daily. On GD19, following final MAP measurement,rats were placed in metabolic cages for 4 hours for urine collection.Urine samples were centrifuged and the supernatant analyzed by ratalbumin ELISA to test for albuminuria.

Compounds described in this disclosure showed reduction in MAP andalbuminuria compared with vehicle on Day 19, indicating improvement ofgestational hypertension and proteinuria associated with preeclampsia.

Other embodiments are within the scope of the following claims.

What is claimed is:
 1. A compound of formula (I) or a pharmaceutically acceptable salt thereof: AA1-Arg-Val-AA4-AA5-His-Pro-AA8-OH   (I), wherein AA1 is an amino acid residue selected from the group consisting of sarcosine and ((2S,3R,4R,5R)-2,3,4,5,6-pentahydroxyhexyl)glycine; AA4 is an amino acid residue selected from the group consisting of tyrosine or meta-tyrosine, each of which is optionally substituted with at least one substituent selected from the group consisting of halo and hydroxyl; AA5 is an amino acid residue selected from the group consisting of valine, leucine, isoleucine, glycine, alanine, phenylalanine, threonine, lysine, and tyrosine, each of which is optionally substituted with at least one substituent selected from the group consisting of C₁₋₆ alkyl, C₄₋₆ cycloalkyl, NH₂, aryl, and heteroaryl; and AA8 is an amino acid residue selected from the group consisting of 1-naphthylalanine, (3-benzothienyl)alanine, and phenylalanine substituted with at least one substituent selected from the group consisting of C₁₋₆ alkyl, C₁₋₆ haloalkyl, C₄₋₆ cycloalkyl, halo, CN, aryl, and heteroaryl, in which the at least one substituent is at the 2-position on the phenyl ring of the phenylalanine; wherein AA8 is a D-amino acid residue, and each of Arg, Val, AA4, AA5, His, and Pro in formula (I) is an L-amino acid residue.
 2. The compound of claim 1, wherein AA4 is tyrosine optionally substituted with at least one substituent, in which the at least one substituent is at the 3-position on the phenyl ring of the tyrosine.
 3. The compound of claim 2, wherein AA4 is tyrosine, meta-tyrosine, 3-hydroxytyrosine, or 3-chlorotyrosine.
 4. The compound of claim 1, wherein AA5 is an amino acid residue selected from the group consisting of valine, leucine, isoleucine, glycine, alanine, phenylalanine, threonine, lysine, and tyrosine, each of which is optionally substituted with at least one substituent selected from the group consisting of CH₃, cyclobutyl, cyclopentyl, cyclohexyl, NH₂, thienyl, and thiazolyl.
 5. The compound of claim 4, wherein AA5 is valine, isoleucine, cyclobutylglycine, cyclopentylglycine, cyclohexylglycine, cyclohexylalanine, leucine, o-methyl threonine, lysine, phenylalanine, tyrosine, 4-aminophenylalanine, 3-thienylalanine, 2-thienylalanine, or 4-thiazolylalanine.
 6. The compound of claim 5, wherein AA5 is valine, isoleucine, cyclopentylglycine, cyclohexylglycine, or O-methyl threonine.
 7. The compound of claim 1, wherein AA8 is an amino acid residue selected from the group consisting of D-1-naphthylalanine, D-(3-benzothienyl)alanine, and D-phenylalanine substituted with at least one substituent selected from the group consisting of CH₃, CF₃, Cl, Br, CN, and phenyl.
 8. The compound of claim 1, wherein AA8 is D-1-naphthylalanine, D-(3-benzothienyl)alanine, D-2-chlorophenylalanine, D-2-bromophenylalanine, D-2-methylphenylalanine, D-2-trifluoromethylphenylalanine, D-2-cyanophenylalanine, D-2-phenylphenylalanine, D-2,4-dichlorophenylalanine, or D-2,6-dimethylphenylalanine.
 9. The compound of claim 1, wherein AA1 is sarcosine.
 10. The compound of claim 9, wherein AA4 is tyrosine, meta-tyrosine, 3-hydroxytyrosine, or 3-chlorotyrosine.
 11. The compound of claim 10, wherein AA5 is valine, isoleucine, lysine, tyrosine, 4-aminophenylalanine, cyclohexylalanine, cyclopentylglycine, cyclohexylglycine, phenylalanine, O-methyl threonine, 3-thienylalanine, 2-thienylalanine, or 4-thiazolylalanine.
 12. The compound of claim 11, wherein AA8 is D-1-naphthylalanine, D-(3-benzothienyl)alanine, D-2-chlorophenylalanine, D-2-bromophenylalanine, D-2-methylphenylalanine, D-2-trifluoromethylphenylalanine, D-2-cyanophenylalanine, D-2-phenylphenylalanine, D-2,4-dichlorophenylalanine, or D-2,6-dimethylphenylalanine.
 13. The compound of claim 1, wherein AA1 is ((2S,3R,4R,5R)-2,3,4,5,6-pentahydroxyhexyl)glycine.
 14. The compound of claim 13, wherein AA4 is tyrosine.
 15. The compound of claim 14, wherein AA5 is valine or cyclohexylglycine.
 16. The compound of claim 15, wherein AA8 is D-1-naphthylalanine, D-(3-benzothienyl)alanine, D-2-chlorophenylalanine, D-2-methylphenylalanine, or D-2-phenylphenylalanine.
 17. The compound of claim 1, wherein the compound is (1) Sar-Arg-Val-Tyr-Val-His-Pro-(D-1Nal)-OH; (2) Sar-Arg-Val-Tyr-Lys-His-Pro-(D-1Nal)-OH; (3) Sar-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2-CF3))—OH; (4) Sar-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2-Cl))—OH; (5) Sar-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2-CN))—OH; (6) Sar-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2-Ph))-OH; (7) Sar-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2,4-diCl))—OH; (8) Sar-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2,6-diMe))-OH; (9) Sar-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2-Me))-OH; (10) Sar-Arg-Val-Tyr-Val-His-Pro-(D-(3-benzothienyl)alanine)-OH; (11) Sar-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2-Br))—OH; (12) Sar-Arg-Val-Tyr-Tyr-His-Pro-(D-1Nal)-OH; (13) Sar-Arg-Val-Tyr-Aph-His-Pro-(D-1Nal)-OH; (14) Sar-Arg-Val-Tyr-Cha-His-Pro-(D-1Nal)-OH; (15) Sar-Arg-Val-Tyr-Cpg-His-Pro-(D-1Nal)-OH; (16) Sar-Arg-Val-Tyr-Phe-His-Pro-(D-1Nal)-OH; (17) Sar-Arg-Val-Tyr-Thr(Me)-His-Pro-(D-1Nal)-OH; (18) Sar-Arg-Val-Tyr-Cpg-His-Pro-(D-Phe(2-Cl))—OH; (19) Sar-Arg-Val-Tyr-Chg-His-Pro-(D-Phe(2-Cl))—OH; (20) Sar-Arg-Val-Tyr-Aph-His-Pro-(D-Phe(2-Cl))—OH; (21) Sar-Arg-Val-Tyr-Thr(Me)-His-Pro-(D-Phe(2-Cl))—OH; (22) Sar-Arg-Val-Tyr-(3-Thi)-His-Pro-(D-Phe(2-Cl))—OH; (23) Sar-Arg-Val-Tyr-(2-Thi)-His-Pro-(D-Phe(2-Cl))—OH; (24) Sar-Arg-Val-Tyr-(Ala(4-Thz))-His-Pro-(D-Phe(2-Cl))—OH; (25) Sar-Arg-Val-Tyr-Ile-His-Pro-(D-Phe(2-Cl))—OH; (26) Sar-Arg-Val-Tyr-Chg-His-Pro-(D-Phe(2-CF₃))—OH; (27) Sar-Arg-Val-Tyr-Chg-His-Pro-(D-Phe(2-Me))-OH; (28) Sar-Arg-Val-Tyr(3-Cl)-Val-His-Pro-(D-Phe(2-Cl))—OH; (29) Glac-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2-Cl))—OH; (30) Sar-Arg-Val-(m-Tyr)-Val-His-Pro-(D-Phe(2-Cl))—OH; (31) Glac-Arg-Val-Tyr-Chg-His-Pro-(D-Phe(2-Cl))—OH; (32) Sar-Arg-Va1-DOPA-Val-His-Pro-(D-Phe(2-Cl))—OH; (33) Sar-Arg-Val-Aph-Val-His-Pro-(D-Phe(2-Cl))—OH; (34) Sar-Arg-Val-Tyr-Chg-His-Pro-(D-1Nal)-OH; (35) Sar-Arg-Val-Tyr-Chg-His-Pro-(D-(3-benzothienyl)alanine)-OH; (36) Sar-Arg-Val-Tyr-Chg-His-Pro-(D-Phe(2-Ph))-OH; (37) Glac-Arg-Val-Tyr-Val-His-Pro-(D-1Nal)-OH; (38) Glac-Arg-Val-Tyr-Val-His-Pro-(D-(3-benzothienyl)alanine)-OH; (39) Glac-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2-Ph))-OH; (40) Glac-Arg-Val-Tyr-Chg-His-Pro-(D-1Nal)-OH; (41) Glac-Arg-Val-Tyr-Chg-His-Pro-(D-(3-benzothienyl)alanine)-OH; (42) Glac-Arg-Val-Tyr-Chg-His-Pro-(D-Phe(2-Ph))-OH; (43) Glac-Arg-Val-Tyr-Cpg-His-Pro-(D-Phe(2-Cl))—OH; (44) Glac-Arg-Val-Tyr-Cpg-His-Pro-(D-Phe(2-Me))-OH; (45) Glac-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2-Me))-OH; or (46) Glac-Arg-Val-Tyr-Chg-His-Pro-(D-Phe(2-Me))-OH.
 18. The compound of claim 1, wherein the compound is: (4) Sar-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2-Cl))—OH; (9) Sar-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2-Me))-OH; (29) Glac-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2-Cl))—OH; (31) Glac-Arg-Val-Tyr-Chg-His-Pro-(D-Phe(2-Cl))—OH; (45) Glac-Arg-Val-Tyr-Val-His-Pro-(D-Phe(2-Me))-OH; or (46) Glac-Arg-Val-Tyr-Chg-His-Pro-(D-Phe(2-Me))-OH.
 19. A pharmaceutical composition, comprising the compound of claim 1 and a pharmaceutically acceptable carrier.
 20. A method of treating hypertension, comprising administering to a patient in need thereof an effective amount of the pharmaceutical composition of claim
 19. 21. The method of claim 20, wherein the hypertension is induced by pregnancy.
 22. A method of treating preeclampsia or a renal disease induced by pregnancy, comprising administering to a patient in need thereof an effective amount of the pharmaceutical composition of claim
 19. 